This invention relates to a vacuum-type electric circuit breaker comprising a plurality of vacuum-type circuit interrupters which are operated substantially simultaneously during circuit-breaker operation and, more particularly, relates to a circuit breaker of this type that employs a common mechanical operator at ground potential for operating the interrupters.
A typical circuit breaker of this type is shown in U.S Pat. No. 3,839,612--Badey et al, assigned to the assignee of the present invention. In this circuit breaker the interrupters are electrically connected in series in order to enable the circuit breaker to handle the required high voltages. Substantially simultaneous operation of the interrupters is required in order to effect the desired uniformity of voltage distribution between the interrupters during operation. In this respect, the contacts of all the interrupters should part within a predetermined maximum time period during an opening operation, e.g., 1/2 to 1 millisecond, and should engage during a predetermined maximum interval during a closing operation, e.g., 1 to 2 milliseconds.
For effecting such substantially simultaneous operation, the interrupters are connected to a common operator at ground potential through operating rod structure which comprises a plurality of insulating rods mechanically connected in series. In this type of arrangement, it is difficult to limit to the desired extent the timing variations between the interrupters because of the differences in the stiffness of the couplings between the common operator and the respective interrupters.